1. Related Application
Application Ser. No. 301,276, entitled "Liquid Smoke-Impregnation of Fibrous Casings", filed contemporaneously with this application in the name of Herman S-G. Chiu, incorporated herein by reference.
2. Field of the Invention
This invention relates to a liquid smoke-impregnated food casing of the fibrous reinforced cellulosic type.
Surface appearance, odor and flavor are important factors in the commercial and consumer acceptance of processed meat products, and a common feature of most varieties of such products involves the use of "smoking" for imparting characteristic flavor, odor and color thereto. The "smoking" of food products has been generally accomplished by subjecting the foot product to actual contact with smoke in a gaseous or cloud-like form. Such "smoking" processes, however, have not been considered completely satisfactory for a variety of reasons, including the inefficiencies and lack of uniformity of the "smoking" operation. Because of the shortcomings experienced, many meat packers now employ various types of aqueous solutions of wood-derived smoke constituents, commonly called "liquid smoke solutions", in the processing of many types of meat and other food products.
The application of "liquid smoke solutions" to meat products is generally carried out in a variety of ways, including spraying or dipping an encased food product during the processing thereof, but this is not completely satisfactory because of inability to uniformly treat the encased product. Another method is to incorporate the liquid smoke solution in the recipe itself, but this does not always provide the desired surface appearance because of dilution of smoke ingredients. Also, incorporation of liquid smoke in the recipe reduces the stability of the meat emulsion, and will adversely affect taste if high concentrations are used. Spray or dip application of liquid smoke to encased food products also causes unwanted pollution and equipment corrosion problems for the food processor. In addition, encased foodstuffs treated by application of the liquid smoke during commercial processing have been found to yield sausages which are lacking in smoke color uniformity between different sausages from the same processed group. Even more undesirable is the lack of color uniformity which often appears on the surface of the same sausage, such as light and dark streaks or blotches, and even uncolored spots, particularly at the sausage ends.
It has been found that casings affording special treatment or structural characteristics to the food product can be more uniformly and economically supplied by the casing manufacturer. Accordingly, it would be desirable for the casing manufacturer to provide a liquid smoke-impregnated casing which could be used by the food processor to impart smoke flavor, odor and color to the food outer surface after stuffing in the casing and during the elevated temperature processing of the encased product.
Liquid smoke often is a solution of natural wood smoke constituents prepared by burning a wood, for example, hickory or maple, and capturing the natural smoke constituents in a liquid medium such as water. Alternatively, the liquid smoke to be used may be derived from the destructive distillation of wood, that is, the breakdown or cracking of the wood fibers into various compounds which are distilled out of the wood char residue. Aqueous liquid smokes are generally very acidic, usually having a pH of 2.5 or less and a titratable acidity of at least 3%.
Reference to the term "smoke color, odor and flavor constituents", as used throughout this specification with respect to liquid smoke compositions and the liquid smoke-impregnated casing article of this invention, is intended to refer to, and should be understood as referring to, the smoke coloring and flavoring and odor constituents derived from liquid smoke solutions in their commercially available form.
The liquid smoke used to prepare the article of this invention is derived from natural wood smoke constituents. The source liquid smoke is generally produced by the limited burning of hardwoods and the adsorption of the smoke so generated, into an aqueous solution under controlled conditions. The limited burning keeps some of the undesirable hydrocarbon compounds or tars in an insoluble form, thereby allowing removal of these constituents from the final liquid smoke. Thus, by this procedure, the wood constituents previously considered desirable by the manufacturer of the liquid smoke are absorbed into the solution in a balanced proportion and the undesirable constituents may be removed. The resultant liquid smoke solution still contains a significant concentration of tars, because the manufacturers and users of the liquid smoke consider the dark colored tars to be necessary from the standpoint of imparting smoke color, odor and flavor to foodstuffs.
Smoke treatment is quite expensive, and it has been assumed in the meat packing industry that to achieve the darker smoke color characteristic on the surface of a meat product, the encased meat product must be subjected to a more extensive treatment with smoke. This has typically been accomplished by increasing the treatment temperature, the contacting time, or the concentration of the liquid smoke, all of which result in increasing processing cost.
The casing articles of this invention are tubular in form, and of the cellulosic type. Also, these casings require a fibrous reinforcement in the casing wall in order to provide for dimensional stability when the casing is impregnated with liquid smoke and to provide dimensional uniformity when the casing is stuffed with a foodstuff. It has been found that cellulosic casing which is subjected to the same liquid smoke treatment level but which does not have a fibrous web in the casing wall, becomes dimensionally irregular in the treatment process and lacks dimensional uniformity in the stuffing process. Accordingly, the casings useful in the present invention are the fibrous reinforced cellulosic type. Generally, these fibrous casings are used to produce encased foodstuffs having a stuffed diameter in the range of from about 40 mm to about 160 mm, or even higher.
In the preparation and use of fibrous cellulosic food casings, the moisture content of the casings is of considerable importance. By way of non-limiting illustration, the casings may be shirred, ie. compressed into a tightly compacted and pleated form, before stuffing on a machine which first deshirrs a casing "stick" and then stuffs the inflated casing. To facilitate shirring operations on these casings without damaging them, it is generally necessary that they be of relatively low water content, usually in the range of from about 11% to about 17% by weight of total casing, a moisture content which is relatively low compared to the moisture content required when the casing is used for food stuffing. To permit shirred casing to be stuffed without breaking of the casing during the stuffing operation, shirred fibrous casings having an average moisture content of between about 17% to about 35% are required. This lower limit of moisture content is important during stuffing, because excessive breakage of the casing has been found to occur at lower moisture contents.
Here it is of importance to note that the term "moisture content" as used throughout this specification and in the appended claims with reference to the liquid smoke smoke-impregnated fibrous cellulosic casing articles of the invention, is intended to refer to and should, unless otherwise specified, be understood as referring to: the weight percent of water or moisture in the casing based on the total weight of the casing.
Even if large size casings are to be used in the flattened form for stuffing without conversion to the shirred stick form, such large size casings are quite stiff in the dry stock form, and are softened for stuffing operation by soaking in water, usually for about an hour, resulting in full moisture saturation of the casing to about 60% by weight of the total casing. Because of this full saturation soaking just prior to use in stuffing operations, the need to supply such casings with any predetermined controllably added moisture content for stuffing operations has not been necessary or even advantageous. The recent wider use of automatic high speed high pressure stuffing equipment for products employing large size tubular food casings, and the consequent increased demand for such casings in shirred form as compared to the short, flattened lengths heretofore used, has brought focus to bear on and has emphasized the problems of moisturizing such casings by soaking just prior to use. Moreover, the need for greater control of all aspects of the manufacture and use of large size food casings has been and is increasing. For example, the uniformity of dimensions of stuffed food casings and food products processed therein has become an increasingly important commercial requirement, and casing moisture content has been found to be a factor in control of uniformity, as well as in meeting the continuing need to readily, and economically stuff the casings without damage or breakage thereof, and more importantly, to permit the stuffing of a given casing to its manufacturer's recommended fully stuffed size with consistent accuracy and reproducibility of results (size uniformity).
A commercially practiced solution to the moisture problem is for the casing manufacturer to premoisturize the casing prior to shirring and/or stuffing so that the casing contains preferably between about 17% and 35% by weight of water based on the total fibrous casing weight. It may then be shirred or reeled in the flat form in the "no soak" form, ready for stuffing. Also, to prevent mold growth in the cellulosic fibrous casing during storage of the casing, an antimycotic agent such as propylene glycol is incorporated into the casing. As, for example, described in copending application Ser. No. 157,008 of Ellis et al, said application being assigned to the same assignee as the instant application, propylene glycol is provided in an amount of at least about 4% by weight of dry cellulose and also sufficient to comprise at least about 5% by weight of the liquid components in the casing.
An object of this invention is to provide a liquid smoke impregnated fibrous reinforced cellulosic food casing article which has sufficient antimycotic quality to be free of mold growth, but without the use of an agent added only for antimycotic action, i.e., in situ antimycotic capability.
Another object is to provide such an article with in situ antimycotic capability and which also has sufficient moisture content to permit subsequent use in food processing without the need for additional moisturizing.
A further object is to provide a liquid smoke impregnated fibrous reinforced cellulose food casing article with in situ antimycotic capability, substantial moisture content, and an optimum liquid smoke loading to impart a characteristic dark smoke color to the outer surface of encased food, while maintaining acceptable smoke odor and flavor characteristics.
Other objects and advantages of the invention will become apparent from the ensuing disclosure and appended claims.